An overweight man or women who's appearance resembles a mixture of a Hippopotamus and a Puffer Fish.

Skinny Dave: "Look at the state of that, he is a beast!"
Thin Bob: "He looks like some sort of animal"
Skinny Dave: "Yeah I know what you mean, like a hippo or maybe a puffer fish"
Thin Bob: "A Hipperpufferfish?"
Skinny Dave: "Exactly, a Hipperpufferfish!"